Aim: The aim of this study is to investigate the dosimetric effects of rotational uncertainties in patient positioning on target coverage in stereotactic radiosurgery (SRS) of multiple brain metastases using single isocenter volumetric modulated arc therapy (VMAT).
Materials And Methods: Ten SRS cases with multiple brain metastases (2-8) planned with single isocenter non-coplanar VMAT technique were investigated in this study. Pitch, yaw and roll displacements of 1, 3 and 5° were simulated about isocenter along each axes and nine plans were obtained for each case.